When I had a TacT preamp serviced once in the past, they sent it back to me with the digital audio output enabled without telling me even though it was disabled when I sent it to them. When I hooked it up to my McCormack DNA-500, it caused a massively horrible sound out of my Gallo 3.0s as soon as I hit play on the CDP. I turned it off quickly, but when I looked at the Gallos the tweeters had holes burned right through them. Turns out that enabling the digital output for some reason also set the analog preamp out at full line out so all 500 watts were surged into the speaker. Fun times.